How do you deal with condo association members who only want to pay for repairs that benefit their use?

Your governing documents are definitive about who pays for what.

Generally, if a repair benefits some but not all of the association's members, then some, but not all of the association's members pay for the repair. This may or may not be true in your specific case.

All members own all the real estate assets involved in the community, and are required to pay -- either by assessment contribution to reserves, or by special assessment -- for repairs, except as specified in your governing documents.

Members who refuse to pay if they are required to pay, can be fined by the board, or the board can file liens on their units for the owed amounts.